1. Field of the Invention
The present invention relates to a dehumidifier for removing the moisture in the air by heat exchange.
2. Description of the Related Art
Such type of a prior art dehumidifier is disclosed in Japanese Utility Model Publication No. 57-59820, in which a cooling zone is defined by an inner housing and an evaporator accommodated therein. A precooling zone is defined between the inner housing and a cylindrical outer housing in which a heat transfer pipe is accommodated. Both end openings of the outer housing are sealed by covers welded thereto.
Hot end moist air passes through the precooling zone, and thereafter through to the cooling zone. The air passing through the cooling zone is allowed to escape to the outside through the heat transfer pipe. The moisture in the air is removed when it is cooled in the cooling zone, and the dehumidified cool air flows through the heat transfer pipe. Accordingly, the hot and moist air flowing in the precooling zone can be precooled by the cool air in the heat transfer pipe.
The foregoing conventional dehumidifier consists mainly of iron members, and rust is caused by the hot and moist air passing through the dehumidifier. Accordingly, the wall thickness of the dehumidifier must be increased in order to take the rust effect into consideration. This will increase the size and weight of the dehumidifier. There is also a possibility that rust will contaminate the dry air to be discharged.
Both end openings of the outer housing are sealed by the covers which are welded thereto. However, the welding of the covers requires professional staffing, and also the welded products do not usually maintain their initial quality and reliability. Besides, most of the parts inside the outer housing are fixed by welding, so that intricate, laborious and time-consuming welding operations are required to produce the dehumidifier. Further, since the covers are directly welded to the outer housing, the apparatus cannot be easily disassembled to maintain the various components of the dehumidifier.
If the quantity of heat in the incoming hot and moist air is above the heat exchange capacity of the dehumidifier, an additional unit for assisting in cooling the dehumidifier will be required.